Long was the son of the flamboyant Louisiana Governor and Senator Huey P. Long. Huey Long was succeeded by his wife Rose McConnell Long, who served approximately a year in the Senate. When Russell was elected in November 1948, he became the only person in American history to have been preceded in the Senate by both his father and his mother. Before running for the Senate, he served as executive counsel to his uncle, Earl K. Long, who also served as governor of Louisiana.
Long was best known for his knowledge of tax laws. In 1953, he began serving on the tax-writing Senate Finance Committee and was its chairman from 1966 until Republicans took control of the Senate in 1981. During his time in the Senate, Long was a strong champion of tax breaks for businesses, once saying, "I have become convinced you're going to have to have capital if you're going to have capitalism."
Long's contributions to the United States' tax laws include the Earned Income Tax Credit, a program aimed at reducing the tax burden on poor working families. He also initiated the provision that allows a taxpayer to allocate $1 of taxes for a presidential campaign-financing fund.
His fellow party Senators elected him Democratic whip in 1965, but he began drinking heavily and often was seen drunk on the Senate floor. He lost his leadership position in 1969. He later quit drinking and soon regained his reputation among his colleagues.
At the time of his death due to heart failure, Russell Long was the earliest Senator still living.